Two metallacyclophanes have been assembled by self-assembly processes involving the trianionic compartmental ligand (L3-), nickel(II) and sodium or potassium ions: [LNiNa]2·C2H5OH·2H2O (1) and [LNiK]2·C2H5OH·2H2O (2) (the Schiff-base proligand, H3L, is obtained by condensation of o-vanillin and DL-2,3-diaminopropionic acid). The structures of 1 and 2 can be viewed as resulting from two enantiomeric fragments, {LNiNa/K} connected to each other by the two carboxylato groups. The intramolecular distance between the phenyl rings is 3.64 Å. The sodium/potassium ions are coordinated by five oxygens in a planar pentagon. Weak intermolecular sodium/potassium···CH interactions are observed in the packing diagrams of the two compounds. The intra- and intermolecular non-covalent interactions are analyzed through several methods based on electron density, Bader’s QTAIM, non-covalent interactions index and natural bond orbitals. They confirm the in-plane five coordination of the alkali ion, which is of an electrostatic, non-covalent nature and the intermolecular interaction with σ C-H orbitals as well. The diffuse reflectance spectra of the two compounds show characteristic features of square-planar nickel(II) chromophores.